贻贝幼体对湍流的反应不因年龄和光线条件而改变
Larval responses to hydromechanical cues potentially have important effects on larval dispersal andsettlement. This study examined the behavior of mussel larvae (Mytilus edulis) in laboratory-generatedturbulence representative of nearshore currents. We video recorded the behavior of early- and late-stageveligers in a grid-stirred tank at five turbulence levels under light and dark conditions. Water velocitiesand kinetic energy dissipation rates were measured using particle image velocimetry and acousticDoppler velocimetry. We characterized the vertical velocity distributions for sinking, hovering, andswimming modes in still water and calculated the average larval behavioral velocity in turbulence. Instill water, young larvae had more positive (upward) velocities than old larvae, and both stages had morepositive velocities in light than in dark. In turbulence, the mean larval vertical velocity varied from positiveat low dissipation rates to negative at dissipation rates above a threshold of 8.3 ?1022 cm2 s23. At thisthreshold, the Kolmogorov length scale (h ?590mm) was two to three times the mean larval shelllengths (171?56mm), implying that turbulence is detectable even by larvae that are smaller than thesmallest eddies. Responses to turbulence were unaffected by larval age or light conditions and contributedsubstantial behavioral variation. By sinking in strong turbulence, mussel larvae could increase theirflux to the bed in energetic coastal flows, particularly over rough substrates like mussel beds. Theresponse to turbulence by early-stage larvae will also affect their dispersal and may help larvae remainnear coastal populations.